Objective: To evaluate adjuvant chemotherapy use for Stage III colon cancer.
Methods: This analysis included 973 patients with surgically treated stage III colon cancer. Socioeconomic information from the 2000 census was linked to patients' residential census tracts. Vital status through 12/31/02 was obtained from medical records and linkage to state vital statistics files and the National Death Index.
Results: Adjuvant chemotherapy was received by 67%. Treatment varied by state of residence, with Colorado, Rhode Island and New York residents more likely to receive chemotherapy than Louisiana residents. Older age, increasing comorbidities, divorced/widowed marital status, and residence in lower education areas or non-working class neighborhoods were associated with lower chemotherapy use. Survival varied by state but after adjustment for sex, sociodemographic and health factors, was significantly higher only for California and Rhode Island. Older age and lower educational attainment were associated with lower survival. Chemotherapy was protective for all comorbidity groups.
Conclusion: Although adjuvant chemotherapy for Stage III colon cancer improves survival, some patients did not receive standard of care, demonstrating the need for cancer treatment surveillance. Interstate differences likely resulted from differences in local practice patterns, acceptance of treatment, and access.
Keywords: adjuvant chemotherapy; colorectal cancer; patterns of care.